You must register for a developer account with DBS (free of charge) to access the documentation. The API is very well documented.

This API also has a Sandbox Environment for you to test in. The Sandbox Environment only allows one Transaction (Request) per second for a given Application and API Operation.

DBS (The Development Bank of Singapore Limited | DBS Group) is a leading financial services group in Asia. They are headquartered in Singapore, with a growing presence in Greater China, Southeast Asia and South Asia.